Grinding machine



Dec. 27, 1938. c, E, TBRQWN I 2,141,853

GRINDING MACHINE Filed Jan. 18, 1936 8 Sheets-Sheet l Car/ion E'uyene firown M.FW

Dec. 27, 1938. c. E. BROWN 2,141,853

GRINDING MACHINE Filed Jan. 1a, 1936 8. Sheets-Sheet 2 t y Q N Q L)\\ kg 5 0 GRINDING MACHINE Filed Jan. 18, 1956 8- Sheets-Sheei 3 t f 9 59\ I 5 1F. e T15 5 9/ 22 95 10g] :1 6 /03 6 T 00 I 83 3mm Caz-Zion Euyerzefirown J -J fig)? ram Dec. 27, 1938. c. E. BROWN GRINDING MACHINE 8 Sheets-Sheet 4 Filed Jan. 18, 1936 Dec. 27, 1938. c. E. BROWN GRINDING MACHINE Filed Jan. 18, 1936 l 'ln l/ 8 Sheets-Sheet 6 Cal-Zion EuyeneBrown c. E. BROWN GRINDING MACHINE Dec. 27, 1938.

8 Sheets-Sheet 7 Filed Jan. 18, 1936- Dec. 27, 1938.

C. E. BROWN GRINDING MACHINE 8 Sheets-Sheet 8 Filed Jan. 18, 195

R O T N E V m Carlfon Eugene Brown BY I 3 $81M: ATTORNEYS Patented Dec. 27, 1938 PATENT OFFICE 2,141,853 GRINDING MACHINE Carlton Eugene Brown, Cincinnati, Ohio, assignor to Cincinnati Grinders Incorporated, a corporation of Ohio Application January 18, 1936, Serial No. 59,711 I 47 Claims.

This invention relates to grinding machines. One of the objects of this invention is to provide a dependable, compact, and efficient apparatus for grinding, particularly for grinding metal parts of round cross-section, in which high speed of grinding production with minimum manual tension or manipulation may be efiectively carried on. Another object is to provide a grinding apparatus that will be well suited for producing, particularly at high rates of production, ground work pieces or parts that will be of high and uniform precision. Another object is to provide a grinding machine of the so'-called center type that will be capable of a high rate of grinding production without impairment of quality, precision, or uniformity of grinding results. Another object is to provide a grinding machine of the center type capable of achieving substantial savings in time of grinding production. Another object is to provide a grinding apparatus of the above-mentioned character in which numerous heretofore. necessary manual operations or manipulations onthe part of the operator, with attendant time consumption and risk of spoilage of work pieces, may be dependably and inexpensively eliminated. Another object is to provide a grinding apparatus in which the numerous difficulties and disadvantages attendant upon hand or manual gaging of the work being operated upon will be dispensed with in a thoroughly practical, dependable and inexpensive manner. Another object is to provide a grinding apparatus for precision grinding in which high efiiciency of grinding operation may be dependably achieved and in which, more particularly, the conditions under which the grinding operation is carried on'may then be automatically varied as the final grinding step, to bring the work piece to the final or required size or dimension, is approached or reached. Another object is to provide a grinding apparatus of the above-mentioned character in which such factors or conditions under which the grinding operation is carried on as the depth of cut of the grinding element, rate of relative traverse between the work piece and the grinding element, rate of rotation of the work piece, and the like, may be efficiently varied in accordance with and suited to the progressive stages or steps of the grinding operation.

Another object is to provide an' efficient and thoroughly dependable control of the grinding operation particularly with respect to achieving the desired size,or dimension of any one work piece or uniformity of size or dimension of a succession of work pieces, and to carry out such control in such a practical form as will lend itself quickly and readily to manipulation or supervision by any ordinary skilled grinding machine operator. Another object is to provide, in a grinding apparatus of the above-mentioned character, an electromechanical control system and mechanism coacting with the grinding element or elements and the work piece or work pieces, for varying or changing the grinding conditions, in accordance with the progress of the work piece or pieces toward completion, or to halt the grinding operation, or both, that will be thoroughly dependable, easily set, manipulated or controlled by the average skilled operator and, moreover, that will be capable of continued dependable operation under the peculiar working or operating conditions under which grinding operations generally have to be carried on. Another object is to carry out such objects as those pointed out above by way of apparatus and mechanism that will be well adapted to meet the varying conditions of hard practical use. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of .elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which are shown several of the various possible embodiments of certain .features of my invention,

Figure 1 is a front elevation of the complete grinding machine or apparatus;

Figure 2 is a plan view thereof as seen from the top in Figure 1;

Figure 3 is a vertical sectional view on an enlarged scale, as seen along the line 3-3 of Figure 1;

Figure 4 is a vertical sectional view on an enlarged scale through a portion of the machine of Figure 1, being more particularly a section along the line 4-4 of Figure 1, through certain of the table control mechanism;

Figure 5 is a detached plan view on an enlarged scale as seen along the line 5-5 of Figure 3, showing part of the wheel-carriage moving or control mechanism;

Figure 6 is a transverse sectional view as seen along the line 66 of Figure 5;

Figure '7 is a detached and fragmentary view as seen along the line 1-1 of Figure 4;

' nection in the feeddrive of Figure 8 is a sectional view taken along a vertical plane through the starting mechanism and gear box of the machine and more particularly is such a sectional view on an enlarged scale as seen along the line 8-8 of Figure 2;

Figure 9 is a vertical sectional view as seen along the line 99 of Figure 8; a

Figure 10 is a sectional view on an enlarged scale as seen along the line Ill-l0 of Figure 4, showing certain parts of the reversing control mechanism;

Figure 11 is a transverse sectional view on an enlarged scale as seen along the line of Figure 1, showing certain of the mechanical and electrical features of a work-dimension gaging mechanism.

Figure 12 is a vertical sectional view on an enlarged scale through a casing at the front of the machine of Figure 1, showing a main switching structure and part of the actuating mechanism therefor;

Figure 13 is a transverse vertical sectional view as seen along the line |3|3 of Figure 12;

Figure 14 is a vertical sectional view on an enlarged scale showing certain switching mechanism and certain of the actuating or control mechanism therefor, in relation to the grinding wheel;

Figure 15 is a vertical sectional view, as seen along the line |5-| 5 of Figure 5, showing certain of the actuating means for the power conthe grinding wheel carriage;

Figure 16 is a vertical sectional view on an enlarged scale through a casing or housing at the front of the machine, as seen in Figure 1, showing certain switching apparatus partly in elevation and partly in section;

Figure 17 is a diagrammatic showing of the electrical circuit arrangements and of certain of the mechanisms and apparatus interrelated therewith,

Similar reference characters refer to similar 1 ilarts throughout the several views in the draw- Referring firstto Figures 1, 2 and 3, I provide a main frame or bed generally indicated at 30, preferably constructed to be hollow and provided along its forward portion 3|! with longitudinally extending ways 3|. (see also Figure 3) which support for longitudinal sliding movement a table 32. The table 32 is in turn provided,

with suitable ways 33 (Figure 3) upon which are supported the headstock 34 and tailstock 35 (Figures 1 and 2), the headstock and tailstock being thereby adjustably positionable lengthwise of the ways 33, suitable means (not shown) being provided for anchoring or clamping the two stocks in adjusted position. The headstock 34 and tailstock 35 are provided with suitable means for supporting and rotating a work piece W (Figures 1 and 2) and these means may take any suitable form, illustratively a. live center 36 rotatably carried by the headstock 34 and a dead center 31 carried by the tailstock 35; between these centers'the workpiece W may be mounted for rotation and any suitable means (not shown) may be provided to cause the work W to be rotated ordriven, as by a suitable device connecting it to the rotatable center 36. The headstock 34 carries an electric motor 38 connected by suitable driving connections (not shown), en-

closed in the casing-like portions 39 of the headstock 34, to the live center 36 to rotate the latter and to drive the work piece W at a suitable rate of speed.

As is better shown in Figures 2 and 3 the bed 38 is extended rearwardly as at 3|! at substantially right angles to the direction along which the ways 3| extend and is provided with suitable guiding ways 40 on which is slidably mounted a carriage 4|, the slidable movement of which along the ways 48 is therefore in a direction toward or away from the ways 3i and hence the table 32. The carriage 4| is provided with suitable bearings 42, 43 (Figures 1, 2 and 3) in which is rotatably mounted a shaft 44 at the left-hand end of which, as viewed in Figures 1 and 2, is mounted a grinding wheel 45, the latter somewhat overhanging the carriage 4| and the rearward extension 30 of the bed 30. A suitable casing or guard 46 carried by the carriage 4| encloses the grinding wheel 45.

Intermediate of the bearings 42, 43 (Figures 1 and 2) the shaft 44 has secured thereto a suitable pulley 41 about which passes a belt 48 of any suitable character, the carriage 4| and the upper part of the bed extension 30 being suitably recessed or apertured to allow the belt 48 to extend downwardly into the hollow bed extension 30 where it passes over a pulley 49 mounted on a main drive shaft 50 that is carried in suitable bearings (not shown) provided in the bed of the machine. The drive shaft 58 extends to the right (Figure 2) through the side of the bed 30 where it is coupled as by coupling 5| to a suitable source of driving power, such as an electric motor 52.

By such a driving arrangement as that just described, the grinding wheel 45 may be driven at a suitable and preferably high grinding speed and since the carriage 4| is slidably mounted on the ways 40, there is provided any suitable .means, such as an idler pulley (not shown) for maintaining the driving belt 48 suitably taut to insure the driving of the grinding wheel 45 throughout the range of movement of the carriage 4|.

Referring to Figure 3, it will be seen that the grinding wheel carriage 4| has secured thereto and interiorly thereof a nut 53 with which a feed screw 54 is in threaded engagement. The feed screw 54 extends rearwardly of the machine, as viewed in Figure 2, and to the right, as viewed in Figure 3, and is rotatably mounted in a bearing 55 provided in an auxiliary casing or housing 56 mounted at the rear of the bed extension 30, suitable means being provided to hold the feed screw against axial movement. By 'rotation of the feed screw, therefore, the grinding wheel carriage 4| is moved along its ways in a direction depending upon the direction of the rotation of the feed screw 54.

For purposes, some of which are outlined in detail later hereinafter, I provide various and different means for rotating the feed screw 54. Among these means is a source of driving power such as a motor 51 (Figure 3) preferably positioned underneath the casing 56 and suitably supported by or on the rear wall of the bed extension 38 and preferably in sucha way that its shaft extends inwardly of the bed, where it is provided with a sprocket 58.

Mounted in suitable bearings substantially as shown and extending through the bed 3|] from front to rear is a shaft 59 (Figure 3) and its rear or right-hand end extends into the gear casing 58 and has mounted upon it a gear 60 which is in driving relation, through an idler gear 6|, to a gear 62 on the rear end of the feed screw 54, these gears being enclosed within the casing 56. To transmit the drive of the motor 51 to the feed screw 54 through this gearing and by way of the shaft 59, the latter has mounted upon it a sprocket 63 which is in driving connection with the motor sprocket 58 by way of a driving chain 64.

At the front or left-hand end of the shaft 59 (Figure 3) the latter is arranged to have certain other driving connections made thereto. For example, it is desirable that the grinding wheel carriage 4| be shiftable manually. Accordingly, I provide, at the front of the machine a hand crank 65 provided with a handle 66 so selectively geared up or connected to the main cross-shaft 59 as to achieve rotation of the latter and hence movement of the grinding wheel carriage at different rates. The connections or mechanisms may comprise a sleeve 61 (Figure 3) suitably mounted to rotate coaxially with the cross-shaft 59 and provided with clutch teeth 68 at its innerend and a gear 69 at its outer end. Suitable bearing means therefor are provided in the lower end of a housing 18 secured at the front of the bed portion 38 An upward extension of the housing 18 rotatably supports a shaft 1| that extends forwardly of the apparatus (to the left in Figure 3), and it is to the outer end of shaft 1| that the hand crank 65 is secured; adjacent the hand crank 65 there'is mounted on the shaft 1| a gear 12 -which meshes with a gear 13 mounted on the outer end of a shaft 14 that is rotatably mounted in a sleeve or hub 15; the hub 15 is rotatably carried by the sleeve or hub 16 which is in turn rotatably carried by the shaft 1| and has two gears 11 and18 at its inner end. Gear 18 meshes with gear 69 while gear 11 meshes with a pinion or gear 19 fixed to the inner or right-hand end of the shaft 14. The hub or sleeve 15 has secured thereto a disk-like member 88 provided with a, series of circularly arranged holes 8| (see also Figure 1).

The handle 66 (Figure 3) movably supports at its inner end a pin 82 which may be projected into any selected hole 8| in the disk 88, thereby linking the disk 88 and the crank arm 65 together ,to turn as a unit.

When it is desired to give the grinding wheel carriage 4| a-rapid manual movement or a coarse adjustment, the pin 82 is seated into an opening 8| in the disk 88 and the crank arm 65 rotated; the parts described above are thereby caused to rotateas a unit and the gear 69 of the clutch sleeve 61 is rotated by the crank 65 through the gear-18, the cross-shaft 59 being placed in driving connection with the clutch sleeve 61 by a companion clutch member 83 later described in detail.

When, however, it is desired to give the grinding wheel carriage 4| 9. slow manual movement and hence a fine adjustment, the pin 82 (Figure 3) is disengaged from the disk member 88, and the handle 66 and hence shaft 1| with pinion 12 are rotated; but this rotation is not trans- :mitted directly to the gear 18- but indirectly thereto through the reduction gearing 12-13 and 19-11, the gear 18 being as a result much more slowly rotated and thus the amount of rotation of the feed screw 54 per rotation of the crank 65 becomes and is much less than was the case where a rapid movement or coarse adjustment of the grinding wheel carriage is effected.

The companion clutch member 83 (Figure 3) is slidably mounted on the cross-shaft 59 but is splined to rotate therewith, as is indicated in Figure 3, and it is provided with clutch teeth 84 which engage the clutch teeth 68 when the clutch member 83 is moved toward the left, as viewed in Figure 3. This clutch member is shown on a larger scale in Figure 5 of the drawings and it is engaged and shiftable by a forked lever 85 pivoted as at 86 and connected at its other end to a link 81 which extends forwardly through the front wall of the machine bed where the link is connected to an operating lever 88 (Figure 1) at the front of the machine. Accordingly, when the above described manual adjustment or movement of the grinding wheel carriage is desired to be made effective, the lever 88 is operated in a direction to cause the clutch member 83 to be moved into engagement with the clutch sleeve 61, thus completing the drive of the hand crank through the above described selective gearing to the main cross-shaft 59.

Thus, the grinding wheel carriage may be manually moved, set, or adjusted, and as already set forth above, it may be moved under power by the motor 51 (Figure 3) which is in direct driving connection with the main crossshaft 59 and which, due to the gearing or driving ratios employed, may and does effect a relatively rapid movement or traverse of the carriage along the ways 48. There are, however, also provided means for effecting a power-actuation of the grinding Wheel carriage 4| at a relatively slow rate, for purposes later described in detail.

Such means preferably include a suitable source of driving energy or power preferably in the form of an electric motor 90 (Figure 5) suitably mounted or related to the bed 38 of the machine and illustratively positioned to the rear of the rear wall of the front bed portion 38, having its shaft projecting through that wall where it carries a driving pinion 9| (Figures 5 and 6) which meshes with and drives a pinion 92 secured to a shaft 93 suitably mounted by or having bearings in an appropriate bracket 94,'or the like (Figure 5), formed in the machine bed. Pinion 92 has coaxially mounted with respect thereto and drives a worm 95 (Figures 5 and 6). Worm 95 meshes with and drives a worm wheel 96 that is keyed to a shaft 91 (Figure 6) provided with suitable bearings carried in suitable spaced webs integrally formed with the machine bed, substantially as shown in Figure 6; the shaft 91 extends through the right-hand web and is coupled, as by a flexible coupling 98, to a shaft 99 rotatably supported in spaced bearings mounted in a. movably mounted housing I88, the shaft 9.9 having formed thereon or mounted thereon a worm |8| which meshes with a worm wheel I82 keyed or secured to the cross-shaft 59 (see also Figures 5 and 3).

As just noted, the housing I88 is movably mounted and, moreover, is so mounted to bring the worm |8| into or out of driving mesh with the worm wheel I82. A preferred arrangement for effecting this mounting may comprise a pair the housing I 00 is thereby pivotally supported to swing about an axis or position (see Figure 6) that a swinging of the housing I00 in clockwise direction moves the worm IOI out of engagement with the worm wheel I02 and a swinging thereof in reverse direction and intothe position shown in Figure 6 meshes the worm IOI with the worm wheel I02.

Swinging movement of the housing I00 in the last-mentioned direction, that is to mesh the Worm and worm wheel, is limited by appropriate stop means which, referring to Figure 6, may

comprise an adjustable stop in the form of a set screw I01, provided with a lock nut I08, the screw I01 being threaded through an upper horizontal wall extension of the housing I00 to bring it into overlapping relation with respect to the right-hand web I09 of the machine bed and through which the shaft 91 (Figure 6) extends.

As is better shown in Figure 6, the housing I00 has a downward extension whose lower end is formed into a sleeve H0; the right-hand end of the sleeve I I0 is closed by a head III through which slidably extends a rod H2 whose left-hand end is enlarged as at H3 to slidably fit the interior of the sleeve I I0. Between the part H3 and the head III is an expansible helical spring H4, tending always to move the part H2 to the left to an extent limited by the nuts H5 on the outer end of the part H2.

The left-hand portion of the part H3 is slotted or bifurcated and has mounted therein a roller H6 which is to function as a cam follower with respect to a cam H'I keyed to a shaft H8 rotatably mounted in spaced bearings or brackets I I9 and I20 (see Figure 3), shaft H0 thereby extending alongside of the web I09.

If, therefore, shaft H8 is swung to bring the cam II'I into engagement with the roller H6 (Figure 6), the latter, with its plunger arrangement H3 is made to move toward the right to an extent substantially that indicated in Figure 6, and through the compressible spring I I4 movement of the plunger arrangement H3 is transmitted to the worm-housing I00 to swing the latter in counter-clockwise direction to effect interengagement of worm I M with the worm wheel I02. The spring H4 insures such yieldability of movement of the worm toward the worm wheel and provides, when needed, a delayed time interval to achieve and maintain ultimate driving interengagement where, as may be the case at times, the initial upward swinging movement of the worm housing I00 does not find the teeth of the worm in exact position to at once mesh with the teeth of the worm wheel I02. The adjustable stop means I0'I of course limits the ex- .tent of upward swinging of the housing I00 under the action of the cam H1 and spring H4.

With worm IOI and worm wheel I02 thus brought into engagement, the cross-shaft 59 may thus be driven from and by the motor (Figure 5) but at a relatively low speed as compared with the speed of rotation given the cross-shaft 59 by the motor 51 (Figure 3) when the latter is made effective, it being noted that the successive pairs of worms and worm wheels -96 and IOI-I02, are in effect a speed reduction gearing.

Accordingly, the feed screw 54 (Figure 3) is rotated very slowly and correspondingly the movement or adjustment of the grinding wheel carriage 4| along its ways 40 is relatively very slow.

Movement of the cam HI out of the position shown in Figure 6 permits the worm housing I00 to drop downwardly and disengage the worm from the worm wheel, thus interrupting the drive of the cross-shaft 59 from the motor 90.

The control of the power drive of the grinding wheel carriage 4! from the motor 90 is described in detail later herein.

As earlier above indicated, the work W (Figures 1 and 2) can be moved in an axial direction while the grinding wheel 45 acts thereon and this movement is thereby eifected by appropriately moving or shifting the table 32 along its ways 3|. Such movement of the table 32 and work W is, in accordance with certain features of the invention, related, as later described in detail, to the movement of the grinding wheel carriage 4I with the grinding wheel 45 along its ways 40.

For effecting movement of the table 32, the latter, as is better shown in Figure 4, is provided on its under side with a rack I25 extending centrally thereof and intermediate of the ways 3I3I.

With the rack I25 meshes a pinion I26 keyed to the upper end of a vertically extending shaft I21 which is rotatably supported in suitable bearings in the front portion 30 of the bed 30, substantially as shown in Figure 4. Accordingly, rotation of shaft I2'I in one direction or the other effects, through the pinion I26 and rack I25, a correspondingly directional movement of the table 32 and of the work W carried thereby.

Splined to the shaft I21 (Figure 4) is a double-ended clutch member I28 whose position along the shaft I21 is controllable by a clutch fork I29 whose arms engage into the annular groove of the clutch member I28. If the clutch member I28 is moved upwardly, its dogs or teeth are brought into interengagement with corresponding dogs or teeth on the under face of a bevel gear I30 which is suitably mounted for rotation about the axis of the shaft I21 and in a position upwardly of the clutch member I28. Accordingly, the table 32 may be moved in response to a driving of the bevel gear I30.

If the clutch member I28 is moved downwardly, and hence into the position shown in Figure 4, its clutch dogs or teeth at its lower end interengage with corresponding dogs or teeth provided in a friction clutch disk l3I which is gripped between the hub of a worm wheel I32 and an annular plate I33, the latter being pressed toward the worm wheel hub by springs I34 interposed between it and the heads of suitable bolts or screws I35 threaded into and peripherally distributed about the hub of the worm wheel I32. Suitable ring-like parts of appropriate material may be interposed between the clutch disk I3I and the parts I33 and I32 between ter being so adjusted, as by appropriately ten- 65 sioning or loading the springs I34, as to yield if opposition to movement of the table 32 exceeds a certain value.

By way of the bevel gear I30, driving connection is made to a suitable form of manually operable mechanism in order that the table 32 may be moved or adjusted manually. This mechanism may and illustratively does comprise a handwheel I36 at the front of the machine (see Figures 4 and 1), mounted to be rotatable about 7 the axis of a stud shaft I81 mounted in a housing I38 (Figure 4) secured to the front of the machine bed portion 30. Handwheel I36 is keyed to a sleeve I39 which extends into the housing I38 or it is formed into or carries a sprocket I40, the driving chain I of which extends downwardly over a. sprocket I42 pinned to a horizontal shaft I43 that extends into the interior of the front bed portion 30 where it carries a small bevel gear I44 that meshes with the bevel gear I30 above described.

Accordingly, the latter may be manually rotated by the handwheel I36 and the just described chain of driving mechanism and the table 32 and parts carried thereby moved or shifted along the ways 3I as desired, the clutch member I28 being, of course, in upper position.

Considering now the drive of the worm wheel I32 of Figure 4, reference should now be made to Figure 7 in which the coaxial relationof the worm wheel I32 and the vertical shaft I21 appears, the worm wheel I32 meshing with a worm I45 mounted upon or integrally formed with a horizontally extending shaft I46 that is rotatably supported in suitably spaced bearings in an interior housing I41, the latter extending to-. ward and being suitably secured to the front of the bed portion 30. At its front end the-shaft I46 has secured thereto a bevel gear I48 with which constantly mesh bevel gears I49 and I50 which are rotatably mounted upon sleeves. I5I and I52, respectively.

The latter are secured in the housing I41 and they form also bearings for a horizontally extending shaft I53, driven in a manner later described.

Splined upon. the shaft I53 and intermediate of the bevel gears I49 and I50 is a clutch member I54 provided with clutch dogs or teeth at its right-hand and left-hand ends, as viewed in Figure '7, engageable, respectively, according to the position of the clutch member I54, with corresponding clutch dogs or teeth formed in the rings of the hubs of the bevel gear's I50 and Assuming that the shaft I53 is constantly driven, therefore, shaft I46 (Figure '7) and hence worm wheel I32 and vertical shaft I21 (Figure 4) is driven in one direction or the other ac-- cording to whether the clutch member I54 is moved out of its neutral position (as shown in Figure 7), and is in-.driving engagement with bevel gear I49 or bevel gear I50; likewise and as a result, the direction of traverse of the table 32 along its ways 3I is controllable and reversible according to the position of the clutch mem ber I54.

The latter is provided with an annular external recess (Figure 7) into which engages the clutch-shifting fork I 55 (see also Figure 4) whose hub is slidably mounted. on a shaft I56 secured in the front portion of the bed 30. The shifting of the fork I55 takes place in a manner later described in detail..

Further considering the power drive of the table 32 and again "referring to Figure '7, the shaft I53 will be seen to extend toward the left inside of the machine bed portion 30*, terminating in abutting relation to a sleeve-like shaft I51 which is driven as later described and which is arranged to be placed in driving connection with the shaft I53 selectively according to what speed change may be desired. For this latter purpose, the driven shaft I51 has at its right-hand end a spur gear I58 and also clutch teeth or dogs I59,

' tending shaft I 10.

and having to the right thereof a smaller gear 10 I 65 with which gear I60 may be meshed if moved to the right out of its neutral or disconnected position, as now shown in Figure '1, by the shifting fork I62. In such case, shaft I53 is driven at a lower speed inasmuch as the drive is now 5 from the driving member I51 by way of pinion I58, larger gear I64, and then smaller gear I and larger gear I60.

The gear shifting fork I62 is manually shiftable by way of a. handle or lever I66 at the front of the machine (see Figure 1), the latter havin suitable connections (not shown) with the shifting fork I62.

Still referring to Figure '1, the left-hand end of the driving shaft I51, which is rotatably mounted in a bracket or housing I61, mounted interiorly of the machine bed, has keyed thereto a bevel gear I68 which meshes with a bevel gearl69 secured to a horizontally but rearwardly exure 3) and has a bearing at its front end in the bracket or housing I61 (Figure f7) and at its rear end in a lower end portion of a housing "I (Figfrom a shaft I13 (Figures 8 and 2) that is mount- 40 ed in suitable bearings at one end in the housing "I and extends into the interior of the rearward bed extension 30 (see Figure 2) where it is supported in suitable bearings (not shown) and where it is provided with a pulley I14 that is driven by belt I15 from a pulley I16 on the main shaft 50 (Figure 2) through which motor 52 drives the grinding wheel 45 as earlier above described. It is thus seen that, by the arrangement just outlined, the power supplied by the motor 52 (Figure 2) is made available to move the work-carrying table 32 along its ways.

The clutch and speed-change mechanism abovementioned as being included in this driving train may take the form better shown in Figure 8 in 55 which it will be seen that the shaft I13, driven as above-mentioned from the grinding wheel driving motor 52, is provided at its end with a pinion I11 that meshes with a gear I 18 to which is pinned or otherwise secured a clutch member 60 I19 having connections as at I with a friction disk I8I of a multiple disk or plate clutch generally indicated at I82.

Friction disks I83 and I84 are provided for contacting the clutch disk I8I on opposite faces 65 of the latter while the outermost friction disk I83 has bearing against it a clamping plate I85 which is movable along the axis of the gear I18, through the agency of a crank I86, to clamp the three clutch disks between itself and a clutch disk 70 I 81 which is keyed and secured to a specially formed or constructed shaft I88 mounted in suitable spaced bearings carried by the housing part I'he left-hand portion of the shaft I88 is hollow Shaft I10 extends rearwardly 0 and crosswise of the machine bed' and substantially parallel to the main cross-shaft 59 (Figor tube-like in order slidably to receive a clutch controlling rod I90 at whose left-hand end is secured a peripherally extending cam member I9I engageable with the left-hand end of the clamping lever or crank I86 (the latter being pivoted as at I92 to the hub of the clutch plate The right-hand end of the clutch rod I90 is pinned, by pin I93, to a shifter spool I94 that is slidable along the reduced portion of the shaft I88, the latter being slotted to receive the pin I93 and thereby form a splined connection between the shifter spool I94 and the shaft I88.

The outer annular groove of the shifter spool I94 is engaged by the lower forked end of a lever I95, pivoted at I96 (Figure 8) exteriorly of the housing "I, the latter and the housing portion I89 being suitably cut away to bring and maintain the forked arm of lever I95 in proper coacting relation with the shifter spool I94 and accordingly, the shifter spool I94 may be shifted into the position shown in Figure 8, in which the clutch disks are pressed together and the clutch is in power-transmitting condition so as to effect a power-driven movement of the table 32, or the shifter spool I94 may be shifted to the right from the position shown in Figure 8 in which case the cam member I9I is likewise moved and held to of the machine and to the left of the handwheel I36. This control lever may be swung in clockwise or counter-clockwise direction, as viewed in Figure 1 and has connected to it a shaft I98 (Figure 2) which extends through the front portion 30 of the bed 30 to an end portion of the clutch and speed-change casing "I (Figure 2) where it is provided with a suitable bearing or support I89 and where, also, it has secured to it an upstanding lever 200 (Figures 2 and 8) which is connected by a link 20I (Figures- 8 and 2) to the upper end of the spool-shifting lever I95. The clutch I82 (Figure 8) may therefore be conveniently operated from the front of the machine by way of handlever I91.

The shaft I88, driven through the clutch I82 from the driving shaft I13, as above described, extends to the right-hand end of the casing or housing "I (Figure 8) where it is provided with a suitable bearing 202 an intervening portion of the shaft I88 havi'ng a splined portion I88 on which is slidably but non-rotatably mounted a gear cone 204 and to which is keyed a gear cone 205.

Rotatably mounted in suitable bearings in the lower part of the housing "I and substantially underneath but parallel to the shaft I88 is another shaft 206 whose right-hand end carries a bevel gear 201 which meshes with the bevel gear I12 of the above-described shaft I10 (Figures 8, 9 and 7). Shaft 206 has an intermediate splined portion 206 upon which is secured a gear cone 208 for coaction with the slidable gear cone 204, and upon which is slidably but non-rotatably mounted a gear cone 209 for coacti on selectively with the gear cone 205 on shaft I88,

Illustratively, these gear cones each comprises 7 three steps of gears, as shown in Figure 8, and

the various gears are so proportioned as to from the front of the machine.

' give a corresponding range of speed changes in appropriate steps.

Gear cone 204 is engaged by a shifting fork 2 I0 carried by a slidably mounted rod 2I I whereby the gear cone 204 may be shifted with respect to the lower and fixed gear cone 208 and their gears selectively paired to give one range of speed-change of drive from shaft I88 to shaft 206.

The lower shiftable gear cone 209 is engaged by a shifting fork 2I2 secured to a slidably mounted rod 2I3 (Figure 9) and thereby gear cone 209 may be shifted with respect to gear cone 205 to selectively pair their gears for another range of speed-change in transmission.

The shift rods 2H and 2 I3 are slidably carried by suitably formed portions of the housing I1I, extend parallel to each other (see Figure 9), and at their adjacent and spaced ends are toothed as at 2II and 2I3 (Figure 9) for alternate engagement by a gear sector 2 I4 whose gear teeth extend throughout such an are (approximately 180 or less) that the gear sector 2I4 (which is fixed to a shaft 2I5 and thereby can be rotated), engages and slides only one shift rod at a time. Thereby the desired speed ratio of transmission may be conveniently and easily manually selected.

The movement or setting of the gear sector 2I4 (Figure 9) may be controlled from any suitable point or position on the machine and preferably Accordingly, there is provided (see now Figure 1) at the lefthand front portion of the machine a rotatably mounted hand lever 2I6 connected at the outer end of a shaft 2I1 (Figuresl and 2) which extends transversely through and to the rear of the front bed extension 30, where it is connected by a shaft 2I8 and flexible couplings 2I9 and 220 (Figures 2 and 9) to the shaft 2I5 of the gear sector 2I4.

Preferably the hand lever 2I6 (Figure 1) is provided with a suitable spring-pressed plunger (not shown) adapted to coact with an index plate 22I for thereby accurately determining the setting of the hand lever 2I6 and of the abovedescribed shiftabl'e gear cones.

Accordingly, to initiate the power driving of the table 32, after motor 52 (Figure 2) has been set into operation. lever I91 (Figure 1) is actuated to bring about an actuation of the clutch I32 (Figure 8), appropriate selection of speed ratios in the speed-change gearing of Figure 8, by way of lever 2I6 (Figure 1), having theretofore been made; the drive'of the pinion I26 (Figure 4) which meshes with the table rack I25 being completed by way of the shaft I10 (Figure '1) through the gearing or driving train better shown in Figure 7, to the shaft I21 itself. Of course the clutch member I28 (Figure 4) is, for effecting this power drive of the table 32, in its lowermost position. as shown in that figure, clutch shifting fork I29 being manually controlled or set by a lever or handle 222 (Figure 1) mounted at the front of the machine bed portion 30. The drive also, it will be noted, takes place through the reversing gearing shown in Figure '7 and controllable by the shifting fork I which determines the position of the clutch member I54. The latter is to be periodically shifted in order to effect reciprocation of the table 32.

Accordingly, any suitable mechanism for operating these reverse gears and for actuating the and 224 (see Figure l and also Figure 4) adjustably positionable along a suitably formed or shaped portion of the table 32; these dogs are spaced about according to the length of the stroke desired to be given the table 32 and each is positioned (see now Figure 1) to one side of a lever 225 pivoted at the front of the machine bed and having a rearward extension (see Figure 4) thatprojects into the path of movement of the dogs 223224.

Lever 225 is secured to a shaft 226 (Figures 1 and 4) which is rotatably mounted in bearings formed in a suitable housing at the front of the machine bed, substantially as shown in Figure 4, and has keyed to it a lever arm 221 (see now Figure 10) which extends downwardly. Between lever 221 and the clutch shifter I there is interposed a suitable mechanical connection or mechanism, of the so-called load and fire type, for causing the clutch to be shifted out of driving connection with one bevel gear (I49 or' I53 of Figure '7) and into driving connection with the other bevel gear (I56 or I49), at an appropriate point in the swing of the lever 221 in one direction or the other depending upon the direction in which the handle 225 (Figures 4 and 1) is shifted by the table dogs 223-224 (Figure 1). Such load and fire mechanisms are well known and hence the mechanism in question need not be illustrated or described in full detail herein.

It will therefore be sufficient to point out, turning now to Figure 10, that the lower end of lever arm 221 is pivotally connected, as by the pin 226 (seealso Figure 4) to a member 229 which is connected through suitable springs 235 (Figure 4) to two members 230, 23I (Figure 10) slidably mounted upon a rod 232 suitably supported above and in substantial parallelism with the rod I56 (Figures 4 and 10) on which the clutch shifter I55 is slidably supported. Springs 235 preferably surround and are supported by the rod 232. The clutch shifter is provided with recesses 233 and 234 (Figure 10) of greater length than the dimension of lugs 230 and 23W, projecting respectively thereinto, of the slidable members 236 and 23I, respectively.

For the members 230, 23I, there are provided pivotally mounted latches 236 and 231, respectively, pivotally supported as by the pins or studs 238 and 239. These latches are shaped as shown in Figure 10 to be engageable with lugs 230 and 23I of the slidable members 230, 23I, respectively. When interengaged with their respective lugs, as is the latch 231 engaged with the lugs 23 I b in Figure 10, the latch 236 holds the slidable member 230 against movement toward the left and latch 231 holds the member 23I against sliding movement toward the right.

The latches 236, 231 tend to swing downwardly into latching position under the action of their own weight, but lever 221 carries an inwardly directed pin 240 (Figures 10 and 4) which, as the lever arm 221 is oscillated or swung, moves into engagement with the end of one latch or the other to lift it out of latching position. For example, in Figure 10, if the arm 221 is now swung in counter-clockwise direction, the spring interposed between the member 229 and the sliding member 23I becomes tensioned throughout such a movement of the lever arm 221 as is terminated by the lifting of latch member 231 by engagement therewith of the pin 246; the slide member 23I is thereby released and is snapped toward the right, moving clutch shifter I55 with it and thereby, referring now to Figure '7, effects a rapid disengagement of the clutch I54 from the bevel gear I49 and an engagement thereof with the bevel gear I56, thereby effecting a reversal of the direction of drive of the shaft I46 (Figure '1) with resultant reversal of the traverse of the table 32 (Figures 4 and 1) along its ways 3|.

The above described swinging of'lever arm 221 (Figure 10) is effected by the table dog 224 (Figure 1) in engaging the lever 225 to swing it in counter-clockwise direction. A similar series of steps or operations takes place at the end of the following reversed stroke of movement of the table 32 when the dog 223 (Figure 1) is brought into engagement with the lever 225 to swing it in clockwise direction and thus to swing arm 221 (Figure 10) in clockwise direction to tension the spring and subsequently lift latch 236 to release slide member 230 for movement to the left under the action of the tension spring and thereby move clutch shifter I55 to the left (Figures 10 and .7) to disengage the clutch I54 from bevel gear I50 and engage it with bevel gear I49, thereby initiating the succeeding stroke of the table but in reversed direction.

At the right-hand portion (Figure 10) of the housing that contains the abovedescribed load and fire reverse operating mechanism, and preferably exteriorly thereof, there is provided a switch, whose purposes are later described in detail, and arranged to beactuated in a certain synchronous manner with the actuation of the reversing mechanism. This switch comprises a suitable insulating base or panel 242 carrying two switch contacts 243 and 244 provided with suitable terminal connectors to which certain conductors, as later described, may be connected. This panel, preferably mounted on or covered by a detachable casing 245, secured to the housing detachably, as by screw 246, so that access thereto may be gained when needed, is-positioned over or in alinement with a cylindrical bore 241 in the housing itself. I

In this bore 241 is slidably mounted a plunger 248 pressed upwardly by a spring 249 also accommodated in the bore. At its upper end the plunger 248 carries a switch member 250 which may bridge and contact the contacts 243244 to close the circuit of the latter, being held in that bridging relation by the spring 249; movement downwardly of the latter removes the switch member 256 out of bridging relation to the contacts 243, 244 and thus effects an interruption of the circuit of the latter.

'Adjacent its upper end the plunger 248 is provided with a pin 25: which extends through a suitable opening or slot (not shown) in the wall of the bore 241 to hold the latter and hence switch member 250 against rotation and to be engaged in the slot or fork of a bell crank lever 253 (Figure 10) pivotally supported by a pin 254 in a web or bracket of the housing. Lever 253 is in effect a bell crank lever whose other effective arm carries a roller 255 positioned in the path of oscillation of a V-shaped cam 256 secured to a lever arm 251 integrally formed with the lever arm 221 through which the reverse gearing is controlled, as was above described.

I With the spring 249 (Figure 10) always urging and holding the plunger 248 in uppermost position, as shown, the lever cam 256 occupies a position either above or below the roller 255 during the movement of the table 32 (Figure 1) along the machine bed, depending upon the direction of the stroke of movement of the table. In Figure 10 the lever cam 256 is shown in position underneath the roller 255.

Accordingly, as the lever arm 221 is swung at the end of the table stroke, as was above described, lever arm 251 causes the lever cam 256 to be shifted throughout a corresponding arc and thereby, in either direction of swing of the lever cam I56, causes the bell crank lever 253 to be swung in clockwise direction, as viewed in Figure 10, and the downward movement of plunger 248 against the action of spring 249, thereby to open the switch 242. The plunger 248 is in its downmost position at the midpoint of the stroke of swing of the lever cam 256, and during the remaining half of that stroke of swing, the lever cam 256 permits the spring 249 to return the parts to the position shown in Figure 10, in which the switch is again closed and in which the lever cam 256 and roller 255 are again interrelated for a repetition of the above described action when the next swing of the lever arm 251 (now in the opposite direction) is brought about at the end of the reversed stroke of movement of the table 32.

The actuation of the switch, therefore, will be seen to occupy but a relatively short interval of time and by the above described mechanism that time interval is substantially coincident with the time interval during which actual reversal of the table movement is brought about.

Thus the table 32 (Figure 1) may be reciprocated throughout a range of movement commensurate with the length of the work W, thereby to traverse the latter with respect to the operative surface of the grinding wheel 45, but in order to effect an appropriate increment of feed of the grinding wheel carriage 4| (Figure 3) and hence of the grinding wheel 45 toward the work at the end of each stroke of reciprocation of the work W, in order that the grinding wheel effect appropriate and successive removals of metal from the work W, certain other mechanisms are brought into play. Among these is the actuation of the pivotally mounted housing I (Figures 6 and 5) at appropriate intervals, to bring the worm llll (Figure 6) driven by the motor 90 (Figure 5) into driving engagement withthe worm I02 in order thereby and through the driving train above described, to feed the grinding wheel carriage toward the work.

This actuation of the worm Illl (Figure 6) into engagement with the worm IE2 is preferably achieved by way of an electromagnetic means preferably taking the form of a solenoid 260 (Figures 6 and 15) The solenoid 260 is provided with a core 26l and is mounted in any suitable manner exteriorly of the right-hand web I09 (Figure 6) with the axis of the core 26l extending vertically. The core 261 has an upwardly directed extension 262 (Figure 15) that is slidably guided in a suitable web or lug of the housing or bed and is urged or held in uppermost position by a coiled spring 263, the action or tension of which may be adjusted as by the nuts 264. The core extension is provided with a slot 265 (Figure 15) into which extends a lever arm 266 that is keyed to the shaft H8 at its left-hand end, and is pivotally connected to the core extension as by pin 261. Shaft H8, through the lever arm 1 (Figure 6), controls the position of the worm l0l in or out of engagement with the worm 'wheel I02, as was described above in detail.

Spring 263 (Figure 15) is thus opposed by the solenoid 260 and the latter when energized overcomes the pull of thespring 263, compresses the latter beyond the position shown in Figure 15, and holds the shaft I l6 in such a position that the cam arm H1 (Figure 6) is so positioned that pivoted housing I00 and hence worm in! are in lowermost position, the worm being disengaged and held disengaged from the worm I02. As is later set forth in detail, the circuit of the solenoid 260 includes the switch 242 of Figure 10 and bearing in mind the actuation of the latter as above described, the solenoid 260 remains energized throughout any moving stroke of the table 32 as effected through the reverse gearing of Figure 7, and accordingly worm lill is held disengaged from the wormwheel I02 during the same steps in the operation of the apparatus; however, at the end of any stroke of the carriage 32, the table-revers ng control mechanism opens the switch 242 (Figure 10), as was above described, and thus effects deenergization of solenoid 260 during a corresponding time interval. During that interval, therefore, the spring 263 (Figure moves the solenoid core 26I upwardly to swing the shaft H8 and hence cam arm H1 (Figure 6) in counterclockwise direction and into the position shown in Figure 6, thus effecting, in the manner already above described, engagement of the worm I01 with the worm wheel I02, whereby the grinding wheel carriage 4! (Figure 3) is moved toward the left.

However, the above-described mechanisms and features coact with certain other mechanisms and circuits. For example, while the actual table-reversing operation takes place, as was above described in connection with Figures 10 and 7, the work piece W is gaged as to its dimension as resulting from the previous operation thereon of the grinding wheel. This gaging mechanism is mounted, preferably detachably, at the front of the table 32 (Figures 1 and 2) and is generally indicated by the reference character 210 and is shown in transverse enlarged section in Figure 11, to which reference may now be made. In Figure 11 the multiple table structure of the table 32, well known and usual, is indicated, and will be seen to be provided with a longitudinally extending way-like rib 32* at any suitable point along which, preferably as determined by the position of the work W on the table 32, is detachably secured the gaging or sizing device 210. The latter comprises a base 21! shaped to interfit with the rib 32 (Figure 11) and a pivoted clamp member 212, actuated by the screw 213 and engaging underneath the rib 32 for clamping the rib 32 between itself and the base 2", thereby rigidly to secure the base and the parts carried by it to the table.

The frame or base 21! carries a housing or casing 214 provided with an car 215 by which a pin 216 pivots the housing 214 to the frame 21! the housing 214 has an extension toward the right in the form of a tube 211, the latter being conveniently threaded in a suitable opening in the housing 214. At its right-hand end the tubular housing extension 211 has secured to it a head 218 the latter being open at its upper portion as at 219 through which is exposed in an upward direction the arm 28!] of a lever 280, pivoted in the head 218 by a shaft 28| and whose other arm 280 is along one that extends through the tubular housing extension 211 and into the housing 214.' The short arm 280 has mounted in it a contact point 282, made of a suitable wear-resisting material such as a diamond, and this contact point 282 is to contact with and engages the work 75 I arti ce W at the under side thereof substantially as shown ,7 (not shown).

in Figure 11.

To effect an appropriate initial setting of' the gaging device and particularly of the contact point 282 with respect to the work W to give the gaging device its intended range of action and control, as later described in detail, the righthand end of the frame or base 21l is provided with an arcuate slot 283 whose center of curvature is at the axis of the pin 216 and the housing extension 211 is provided with a clamping screw 284 engageable in the slot 283. Thereby the gaging device as a whole may be initially set with respect to the initial dimension or diameter of the work W to insure the desired contact between the latter and the contact point 822. For example, where the diameter of the work W is smaller than that indicated in Figure 11, the clamping screw 284 is loosened and the housing 214-211 is swung upwardly about the pm 216 to set the contact point 282 for engagement, in a manner later described, with the work W (and subsequent work pieces of the same lot) to insure the subsequent range of action of the gaging device as the dimension or diameter of the work W is reduced; For larger diameter of work W, the housing structure may be swung in clockwise direction and thereby lower the contact point 282 with respect to the axis of the work W, in like manner and for like purposes.

Moreover, the parts are so-proportioned and positioned that, as is better shown in Figure 11, the contact pint282 engages the work W at the end of that radius of the latter that is most nearly in line with the slightly curved path of movement of the contact point 282 as deter mined by the length of its lever arm with respect to the axis of the shaft or pin 28L Thereby more faithful response in the movement of contact point 282 and hence in the swinging or positioning of the lever 288 to changes in diameter of the work W is assured.

The lever arm of contact point 282 is relatively small or short as compared to the length of the lever arm 288 at whose outer and left-hand end is carried a conducting element in the form of a plate-like electrode 285 of appropriate or suitable area; the plate member 285 may, if desired, be substantially circular and is preferably in- .sulatingly secured to the lever arm 288 in any suitable way.

With the above described difference in lengths of the lever arms represented by the arm 288 that carries the con act point 282 and the arm 288 which carries t e plate member 285, an amplification or multiplication takes place in that for a relatively small change in position of the contact point 282 a relatively large change in position or displacement of the plate member 285 results, the latter being moved in a general up and down direction, as viewed in Figure 11. Juxtaposed to the plate member 285 is a com panion electrode or plate 286, preferably of the same shape and area as the movable plate 285 and forming with the latter an electrical condenser the electrostatic capacity of which varies or changes with change in the spacing between the two plates, all for a purpose as later described in detail.

The bottom plate member 286 is supported within the housing 214 in any suitable way and preferably adjustably so; also, it is preferably insulated from the housing in any suitable way A preferred adjustable mounting fonthe plate 286 may comprise a screw 281' (Figure 11) threaded through a substantial opening in the bottom of the housing part 214 and having the plate member 285 suitably secured thereto at its upper end; its lower end is preferably provided with a disk-like head 288 which is preferably peripherally graduated, as indicated in Figure 11, a suitable fixed pointer or datum 289 being secured to the bottom of the housing 214 adjacent the graduated head 288, whereby suitable precision of setting of the condenser plate 286 may be achieved.

Preferably the contact point 282 (Figure 11) is arranged so that it is not continuously in contact with the work W but is periodically brought into engagement with the work. Accordingly, there is provided suitable means for holding the lever 288 and hence the contact point 282 in such a position that the latter is out of engagement with the work but may, under controlling means as later described, be released for movement to contact with and gage the work. A preferred arrangement comprises a solenoid winding 298 (Figure 11) housed in a suitable upper portion of the housing 214, the upper and lower walls of which housing portion being shaped also to slidably guide the-core 2! of the solenoid winding 298 and an upward piston rod like extension 292 of the latter which carries a piston 293 slidably fitted into a cylinder 294 formed at the upper part of the housing 214.

At its lower'end the core 29! is linked to the left-hand end of lever arm 288* as at 295, while a, spring 296 in the upper end of the cylinder 294 acts to urge the core 29l downwardly.

The winding 298, which is in circuit with the switch 258 (Figure and Figure 17), may, therefore, when energized, overcome the action of spring 296 and swing and hold lever arm 288 in its uppermostposition, thereby swinging and holding the contact point 282 downwardly away from and out of contact with the work W (Figure 11) Y but if deenergized, it might be noted that deenergization takes place when switch 258 opens at the end of each stroke of reciprocation of the work table 32 and work W (Figure 1), spring 296 is freed to move the lever arm 288 downwardly to an extent permitted by the engagement of the contact point 282 with the work W, an extent which is dependent upon the dimension or radius of the work W.

correspondingly, the capacitance of the condenser 285-286 assumes a value corresponding to the spacing between the plates 285 and 286 as that spacing is determined by the range of movement of the contact point 282 as limited by the dimension of the work W. The manner and means whereby this change in capacitance of the condenser 285-286 coacts with'other elements and achieves certain controls is dealt with in greater detail later.

The piston 293 (Figure 11) and the cylinder 292 are preferably so constructed and interrelated or are made to operate with any suitable fluid medium, such as air or oil, as to give the action of a dashpot and thereby to damp the movements of the gaging lever 288 in response to energization or deenergization of the solenoid 298. For example, when the latter is deenergized, the dashpot action causes the descent of the piston 293 under the action of spring 296 and the resultant counter-clockwise swinging of gaging lever 288 to take place with sufi'icient retardation as will always bring the contact point 282 neatly into engagement with the work W and without danger of marring the surface of the latter or of injuring the contact point itself.

As earlier above indicated, there is a number of mechanisms, means or devices coacting with various of the parts of the machine above described; aside from such devices as the above described gaging device of Figure 11, there is a main control related switch mechanism associated with the main control lever I91 (Figure 1) and by which lever, as above already described, shaft I98 (Figure 2) is swung to actuate the clutch I82 (Figure 8) to set into action the power reciprocation of the work table 32. This shaft I98 passes through a housing 300 (Figure 1) secured to the front wall of the front bed portion 30 of the bed 30 and in Figure 12 the housing 300 is shown in longitudinal vertical cross-section; in Figure 12 the shaft I98 appears in trans verse section and is seen to have secured thereon a bevel gear 30I which meshes with a bevel gear 302 on a shaft or rod 303 slidably mounted in bearings 304305 suitably formed or provided in the housing 300.

Shaft 303, as better appears in Figure 13, is square in cross-section and has mounted upon it and insulated therefrom a number of switch contacts, certain of which are preferably arranged in sets.

Three of these sets of contacts appear in elevation in Figure 12. Going along the shaft 303 from left to light the first set .of contacts comprises contacts 306, 301 and 308, the second set comprises contacts 309, 3I0 and 3II'; and the third set comprises contacts 3I2, 3I3 and 3.

The contacts of these three sets of contacts coact respectively with contacts of three sets of stationary or relatively fixed contact members which are mounted in alinement and in depending relation from a suitable block 3I5 of insulating material suitably mounted in the upper portion of the housing 300 (Figure 12).

from the left to the right, the first companion set of contacts comprises contacts 3I6, 3H and 3I8 for coaction, respectively, with the contacts 306, 301 and 308, in a manner later described, these two sets of contacting contacts forming a switch which, for convenience in later description, will be generally designated and indicated as switch 325.

The second companion set of contacts comprises contact members 3I9, 320 and 32I for coaction, respectively, with movable contacts 309, 3H! and 3I I; these two sets of coacting contacts thus form a switch which, for convenience, will be designated as switch 326.

The third set of companion contacts are co tacts 322, 323 and 324 for coaction, respectively, with movable contacts 3I2, 3I3 and 3 on the rotatable shaft 303, and together they form a switch which will be referred to as switch 321.

Fixed contacts 3I6, 3I9 and 322 have secured at their lower and forward ends, as viewed in Figure 12, blocks '328, 329 and 330, respectively,

of insulating material; see Figure 13 in which the insulating block 328 of spring contact 3I6 appears in side elevation. These blocks of insulating material are provided in order that circuitclosing action between contacts 3063I6, 309- 3I9, and 3I2-322 occurs only when the contactcarrying shaft 303 rotates in one direction relative to the fixed contacts and not when its rotation is subsequently reversed, all for purposes later described.

Furthermore, the contacts of the three sets Again considering the showing of Figure 12 in a direction carried by the shaft 303 are shaped or staggered v so that they engage their respective fixed contacts in certain sequences when the shaft 303 is rotated in counter-clockwise direction, as viewed in Figure 13, that being the direction of rotation that takes place upon starting the entire apparatus in consequence of a counter-clockwise swinging (to the left) of the starting lever I91, as the latter is viewed in Figure 1. This shaping or positioning of, the contacts is sufiiciently indiv:ated in Figure 13.

In Figure 13 contacts 306 and 308 will be seen to be angularly spaced from each other while the intermediate contact 301 is shaped like a brush to maintain a. longer period of contact with its fixed contact member.

Accordingly, when switch shaft 303 is swung in counter-clockwise direction (Figure 13) and hence to bring the three sets of contacts thereon, as viewed in Figure 12, over toward the observer,

contacts 306 and 301 engage fixedspring contacts 3I6 and 3", respectively, thereby closing a circuit later described, but as the swinging of the shaft 303 continues, contact 306 moves out of engagement with fixed contact 3I6, and intermediate contact 301, due to its arcuate shape, maintains contact with fixed spring contact 3I1, during the engagement of contact 308 with fixed spring contact 3I8; the circuit thus first established by contacts 306-301 is interrupted and thereafter a different circuit is closed but now by contacts 301-308.

Swinging the switch shaft 303 in clockwise direction (Figure 13), as occurs when the apparatus is to be stopped as later described, reverses the above-described sequence of events excepting that insulating block 328 on fixed spring contact 3I6 prevents moving contact 306 on the shaft from engagement with the contact 3I6 and hence from effecting a closure of the above-mentioned initially closed circuit.

Moving contacts 309, 3I0 and 3 of switch 326 (Figure 12) and moving contacts 3I2, 3I3 and 3 of switch 321 are shaped respectively like contacts 306, 301 and 308 just described and coact with their respective fixed spring contacts 3I9, 320 and 32I, and 322, 323 and 324, to effect sequential circuit controls just as was above described with respect to switch 325.

Still referring to Figure 12 that portion of the shaft I98 that extends through the housing 300 their normal positions (see Figure 13) also connected to the lower end of the arm 33I is the core 334 (Figurel2) of a solenoid whose winding is shown at 335. Winding 335, when energized, may therefore hold the starting lever I91, switch shaft 303, and related parts, in their operated position against the action of spring 332, the latter becoming effective when the winding 335 is deenergized, all as later described.

Also within the housing 300 (Figure 12) is a switch generally indicated by the reference character 338 and it comprises a fixed contact 336 and a movable contact 331, the latter being insulatingly mounted upon the switch shaft 303 while the former is insulatingly mounted in the housing 300; suitable leads are provided for connecting 2,141.,see

the switch 338 into a circuit as later described. The switch contact 331 (see Figure 13) is arcuate or brush-like in shape so that it maintains contact with the contact 335 throughout a suitable range of swinging movement of the switch shaft 333.

As will later appear more clearly, switch 325 (Figure 12) controls motor 38 (Figure 2) that effects rotation of the work W by way of the headstock 33, switch 325 controls motor 33 (Figure which drives the grinding wheel carriage feed train of gearing, and switch 321 controls motor 51 (Figure 3) which as earlier described is connected up to the grinding wheel carriage 4t may comprise a lever 341 which, with the casing of switch 340 mounted as shownin Figures 3 and 14 at the rear of the front bed extension 3|) but at the forward end of the rear bed extension 30 projects upwardly into the path of leftward movement of the grinding wheel 45 as its carriage is traversed toward the left along ways 40. Lever 3 (Figure 14) carries, preferably adjustably as by way of a suitably lockable thumb screw 342, a wheel-contacting member 343 of any suitable material or construction adapted to be substantially unaffected by the grinding wheel; it may, for example, be a roller, of suitably hardened material, which is thus brought into rolling contact with the rotating grinding wheel 45 and thus resists grinding action thereon.

Within the switch casing a shaft 344 (Figure 14) to which the lever 34! is secured is suitably pivotally mounted and has secured thereto a carrier or bracket 345 in the upper arm of which is mounted a mercury switch 346 and in the lower arm of which is mounted a mercury switch 347], the two electrodes of which are provided with suitable flexible lead wires leading to suitably insulatingly mounted connectors, as is indicated at 343, whereby the two mercury switches may be connected into appropriate circuits as is later described.

The two mercury switches (Figure'l) are so constructed or mounted, for example by arranging them out of parallelism, as indicated in Figure 14, that when one of them is in circuitclosing condition the other is in circuit-opening condition.

For example, switch 346 is shown in Figure 14 as having its electrodes bridged by the mercury therein while switch 341 is in such a tilted position that the mercury does not bridge its electrodes. As the grinding wheel moves toward the left (Figures 3 and 14) it comes into engagement with the part 363 of the operating lever 34!] and swings the carrier 345 in counter-clockwise direc tion, thus to tilt switch 346 out of horizontal and cause its mercury to flow out of electrode-bridging position and to move switch 341 into a substantially horizontal position to cause its mercury content to bridge its electrodes. As will later be set forth in greater detail, the circuit-interrupting action thus brought about in switch 345 is made effective to stop motor 57 (Figure 3) and hence to stop the movement toward the left of the grinding wheel carriage.

ill

The circuit-closing action brought about in switch 3411, as is later explained further, is made effective to energize a magnet or coil 355 (Figure 14) suitably mounted in the switch casing and positioned so that an armature 35E carried by the switch carrier 345 and brought into coaction with the coil 35!] becomes held by the latter, thus holding the switch mechanism 340 in the position in which it has been moved by the grinding wheel, as just above described.

Preferably winding 355 is made sufficiently powerful and the remaining parts so constructed that, once the grinding wheel 45 (Figure 14) has moved the switch carrier to cause mercury switch 346 to break its circuit and mercury switch 341 to close its circuit (thereby energizing winding 350), the coil 350 when thus energized can effect a slight additional counter-clockwise rotation of the carrier 345 to bring it into a secure holding position but particularly also and thereby to move the wheel-contactingmember 343 slightly away (to the left) from the grinding wheel 45 and thus hold it out ofengagement therewith while the grinding operations continue, it being borne in mind that, as above described, the periodic deenergization of switch 250 (Figure in timed relation to the reversals in the strokes of reciprocation of the work carriage 32 is effective to couple the motor 90, through worm l0! and worm wheel I02 (Figure 6) to the grinding wheel carriage drive and thus feed the grinding wheel 45 further to the left.

This switch mechanism 340 is so arranged or balanced that, were the grinding wheel 45 to be sufficiently withdrawn toward the right (Figures 14 and 3) and were the holding coil 350 to be deenergized, the carrier 345 with the operating lever 34i tilt or swing in clockwise direction against a suitable stop (not shown), thereby to restore mercury switch 346 to circuit-closing condition and mercury switch 341 to circuit-opening condition.

To eflect deenergization of holding coil 35!), there is provided on the grinding wheel carriage 4! (see now Figure '3) a earn 355 in theform of a bar extending in the direction of movement of the carriage 4i. Cam 355 has a cam face or edge that is substantially stepped, providing a low cam face 355 and a high cam face 355 Cam 355 controls, according to the position of the wheel carriage 4i lengthwise of its ways, two switches 353 and 351 of any suitable construction, such as the Plunger type of switch, each being provided with a roller for contacting the face or edge of the cam 355, the switches themselves being mounted on the rear bed extension 30*. Both of these switches are arranged so that when their plungers are depressed, as when the carriage 4! is withdrawn and is hence moved toward the right so that the lower cam edge 355* depresses the plunger of the two switches, the cirlit cuits in which these switches are controlled are be illustratively but not by way of limitation a direct current source. From the main circuit 360361 the above described motors receive their energy.

Thus, for example, motor 52 which drives the grinding wheel and the work table reciprocating mechanism (see Figure 2) is shown in Figure 1"! as connected to the power line through a suitable starting or control switch 363 for, as will later be clearer, that motor and hence the grinding wheel may be and preferably are first set into operation and continued in operation.

Headstock motor 38 has a shunt field 38 in series with which is a resistance 364. This motor may also be compounded and hence may have a series field winding 38*. Its connection to the main circuit 360--361 is by way of a suitable starting switch generally indicated by the reference character 365, the switch having a control coil 366. Closure of the switch completes the connection of the motor and. its field circuits from main circuit conductor 361, conductor 380, switch 365, conductor 368, thence through the motor and its shunt field, conductor 369, switch 365, and by way of conductors 310 and 311 back to the main line conductor 360. It is this circuit that is completed upon energization of the control coil 366 and that is broken upon deenergization of the latter, coil 366 controlling the position of the switch 365.

Coil 366 is in turn controlled by switch 325 described above in detail in connection with Figures 12 and 13. More specifically (see Figure 1'!) one side of coil 366 is connected to conductor 310 which leads by conductor 311 to main line conductor 360; the other terminal is connected by conductor 312 to fixed contact 311 of switch 325. A suitable conductor 313 (Figure 1'1) connects fixed contact 316 of switch 325 to the remaining side of the main circuit. Accordingly,v contacts 306 and 301 of switch 325, electrically connected with each other and with contact 308, effect a bridging of fixed contacts 316 and 311 when the switch shaft 303 is first rotated in response to movement of the main starting lever 191 (Figure 1) thereby energizing switch coil 366 (Figure 17) and starting the motor 38.

The subsequent and remaining portion of rotary movement of switch shaft 303, as above described, moves switch contact 306 out of engagement with fixed contact 316, thereby'breaking the above-outlined circuit of switch coil 366, but before that takes place another circuit for coil 366 is completed and retained completed by contacts 301-311 and 308-318; that latter circuit may be traced in Figure 1'! as follows:-main line conductor 360, conductor 311, conductor 310,

switch coil 366, conductor 312, contact 311, contact 301, contact 308, contact 318, conductor 314, switch contact 393, switch member 394, switch contact 395 (of a. switch 396 later described in detail), conductor 319, through switch 365' (now closed), conductor 380 to the other main line conductor 381.

The motor 38 is thus'started and continued in operation. Furthermore, provision is made for changing the speed of that motor and illustraitively that may be brought about by way of conductors 381 and 382 which lead from a portion of the shunt field resistance 364 of motor 38 to a switch 383 that is at this stage open but later closed in a manner later described. Thus, the work piece W is set into rotation by the motor 38 and its speed of rotation may be reduced at a later stage.

-be traced as follows:From main line conductor 360, conductor 311, conductor 310, switch 385, conductor 381, through motor 90, conductor 388, switch 385, and by way of conductor 389 to the other main line conductor 361.

Switch coil 384 is controlled by switch 326.

The first part of the rotary movement of switch shaft 303 causes electrically connected contacts 309, 310 to bridge fixed contacts 319 and 320, completing a circuit for switch coil 384 which extends from main line conductor 361, conductor 390, contact 319, contact 309, contact 310, contact 320, conductor 39!, switch coil 384, conductor 310, conductor 311, to the other mainline conductor 3'60. Switch 385 is thereby closed.

But the continued rotary movement of switch shaft 303 into its final position interrupts that circuit of switch coil 384 but before that interruption takes place has completed a new circuit for coil 384 which circuit is maintained thereafter; that new circuit extends from main line conductor 360, conductor 311, conductor 310, switch coil 384, conductor 391, contact 320, contact 310, contact 311, contact 321, conductor 392, to a switch contact 315, switch member 318, switch contact 311 (of a switch 318 later described in detail), conductor 391 to switch 385 (now closed), and then by way of conductor 389 to the other main line conductor 361.

. The grinding wheel carriage feed drive, subject, however, to connection or disconnection mechanically under the'control of the switch 250 (Figures 10 and 1'!) is thus made operative, but placed under the control of switch 318, just as was the headstock motor 38 placed under the control of switch 396.

Provision is also made to change the speed of drive transmitted by the motor 90 and this may be carried out by way of conductors 398 and 399 which are connected to a suitable portion of the shunt field resistance 386, leading to a switch 400, open at this stage but later closed in a manner later described. Thus,'.the incrementof feed given the grinding wheel carriage may be varied.

Optional provision is also made to change the cutting speed of the tool or grinding wheel and the rate of reciprocation of table 32. This may be carried out by way 'of conductors 555556 which are connected to a suitable portion of resistance 551 in the field 558 of the driving motor 52, conductors 555556 leading to a switch 559 open \at this stage but later closed as described hereinafter.

Motor 51 which drives the rapid traverse gear train-of the grinding wheel carriage 41 (Figure 3) may also be a shunt motor and as shown in Figure 1'! may have a shunt field 51 and that may be and preferably is directly energized from the main line conductors 3'60 and 361 to which it is connected by conductors 401 and 402. The motor 

